# please help in making a lab report on(Velocity Control of the DC-Motor Using Compensators)Objective In this lab, the step-response of a DC-motor will…

In this lab, the step-response of a DC-motor will be “shaped” using a cascade compensator.

We will investigate the effects of two different compensators. A proportional-plus-integral

(PI) compensator, and a slightly more general two-pole two-zero controller, will be designed

to achieve some given step-response specifications. Simulations and hardware experiments

will be used to verify the performance of these compensators in a velocity-control loop.

Pre Lab (Simulation)

Here are the step-response design specifications for closed-loop system behavior:

• Transient Specifications

o Percent Overshoot = 15%

o Settling time = 1.25 seconds

Figure 1. Simulation of the 2-pole motor model and the PI controller. Note that the electrical

time constant has, in this motor model, been assumed to be 0.05 seconds.

Set Ka = 1

a. Using root-locus techniques, determine a PI controller design { A, z } so that in closedloop

a complex-pole-pair will be the dominant poles, and the given step-response

specifications will be satisfied.

b. Simulate the system given in Fig. 1 using the values of A and z from step (a). Determine

the percent-overshoot and settling-time from the simulation and compare them with the

values that you designed for. Why are the simulation results different from the

theoretical values? Sketch the root locus and explain.

c. Design a PID controller ????” ???? = &(()*+)(()*-)

((()./) such that the closed-loop system will

satisfy the specs, and the zeros are both significantly to the right of the pole at -30. The

easiest solution is to place both zeros at the same s-plane location. Sketch the root locus

and analyze your design. Simulate and confirm that the design specs are satisfied.

3. Hardware Experiment

a. The PI controller with the actual DC-motor

Use the values designed in pre-lab part (a) for A and z. Plot the graph of y vs. t. From

the plot, measure the overshoot and the settling time, for later comparison to the given

design specs, and to the simulation results.

Always put a “saturation” block (not shown in this figure) in series with the controller, just

after the Gain “A” block, to enforce limits on the control voltage between -5V and +5V.

That keeps the PWM value between 0 and 255. PWM values outside that range will give

unpredictable – and probably weird – results.b. The PID controller with the actual DC-motor

Use the values designed in pre-lab part (c) for B, z1 and z2. Plot the graph of y vs. t. From

the plot, measure the overshoot and settling time, for later comparison to the given design

specs, and to the simulation results.

Again, be sure to put a “saturation” block (not shown in this figure) in series with the

controller, just after the Gain “B” block, to enforce limits on the control voltage between

-5V and +5V. That keeps the PWM value between 0 and 255.

4. Report

Include the following in the report:

• All design details and root-locus analysis required throughout the lab exercise.

• Comparison of simulation and the hardware results for the two controllers.

• Answers to questions in the pre-lab

(???? + ????2)(???? + ????3)

????(4. Report

Include the following in the report:

• All design details and root-locus analysis required throughout the lab exercise.

• Comparison of simulation and the hardware results for the two controllers.

• Answers to questions in the pre-lab 